The invention concerns more particularly the recording of data on film or also on optical storage such as holographic memory.
The reading of data on such medium can be difficult as the “reading head”, or what can be considered as reading head, is not properly aligned with the data to be read.
Particularly, using film for archiving digital data, and looking for high density storage, becomes a great challenge. Thus, the size of pixels used for recording the data on the film cannot be lower than a certain limit depending on:                the size of particles constituting the film, which vary from 0.2 to 1 micron,        characteristics of the equipment in charge of printing and reading the data on the film, and more particularly on their resolution and stability.        
Moreover, the film ageing over the years can also alter the quality of data on the film, making the scanning of data more difficult.
When scanning the data, the scanner has to be aligned with the data. When data are analog data representing images for instance, the alignment is not crucial during the scanning as there is no need for decoding afterwards. However, when digital data are stored on the film, the scanning becomes crucial, in order to be able to recover the data and decode them. So, if the scanner is not aligned properly with the pixels, the data cannot be recovered properly despite the redundancy data and several pixels will be erroneous.